N,N-Dimethylformamide (3 ml) was added to 6-methoxy-4-(2-methyl-quinolin-3-yloxy)-quinolin-7-ol (compound 352) (50 mg), diethyl 2-bromo-malonate (75 mg), and potassium carbonate (62 mg), and the mixture was stirred at room temperature overnight. Water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with water and was then dried over anhydrous sodium sulfate. The solvent was removed by distillation under the reduced pressure, and the residue was purified by thin layer chromatography using hexane-acetone to give the title compound (134 mg, yield 88%).
